Optimized Reactive Ion Etching/Wet Etching of Thermal Printheads
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
Combining reactive ion etching (RIE) and wet etching processes takes advantage of the RIE ability to form narrrow, deep trenches, and also takes advantage of the economy of batch processing by wet etching. RIE is used sparingly, to form only the electrode section of the printhead. The electrode section is not produced by the less costly wet chemical etching process because undercutting problems would occur. The balance of the head is formed by wet chemical etching. Fig. 1 shows the electrode pattern 1, configured by mask 2, etched in the tungsten sheet 3 by the RIE. The mask 2 is removed. Fig. 2 shows KAPTON* polyester film 4 laminated to the tungsten sheet 3. The laminated sheet is dipped into photoresist 5, and the rest of the head pattern 6 is exposed and developed. The final step is the wet etching.